1. Technical Field
The disclosure relates to a speaker, and particularly to a piezoelectric-type speaker.
2. Related Art
A speaker is an electro-acoustic transducer capable of converting electrical energy into acoustic energy through physical effects. According to different physical effects being applied, the speaker is divided into several types, such as electromagnetic-type speaker, piezoelectric-type speaker, capacitive speaker, and electrodynamic-type speaker. Along with the rapid developments of related technologies, the trend for designing electronic devices is to reduce weight and miniaturize, so people can use the electronic device and the portable stereo earphone anytime and anywhere. When the electronic device plays sounds using the earphone, the original acoustic frequency is converted into a converted acoustic frequency which the user can hear.
The conventional earphone includes a piezoelectric member for reproducing the acoustic frequency in the high-pitched region; additionally, the conventional earphone includes a low-pitched speaker provided for reproducing the acoustic frequency in low-pitched region. Such piezoelectric-type earphone have a lower cost because of the cheaper piezoelectric members used, in contrast to the balance armature speaker (BA speaker). However, conventionally the piezoelectric member is assembled to the low-pitched annular structure, and the high-pitched speaker with piezoelectric member cannot obtain the harmonic oscillation frequency required. Furthermore, upon playing the high-pitched sounds and low-pitched sounds, the crossing point (frequency division point), between the high-pitched speaker and the low-pitched speaker, overlaps with the sounds which are playing, thereby reducing the quality of the sound output by the conventional earphone.